The disclosed invention relates in general to a tape cartridge, and relates more particularly to a brake for stopping the rotation of spools on which the tape is stored. In the following discussion, the first digit of a reference numeral indicates the first figure showing the element referenced by that reference numeral. In a typical data cartridge, there is sufficient inherent frictional resistance in the tape cartridge that a brake is not needed.
In the disc drive compatible tape cartridge illustrated in FIG. 1 and discussed in detail in U.S. patent application Ser. No. 713,162 entitled DISC DRIVE COMPATIBLE TAPE CARTRIDGE filed by Richard H. Henze, et al. on 3/18/85, a tape 10 is directed by a set of guide pins 11-16 in a folded path that passes the tape past a region (denoted by dotted line 17) in which data is recorded and read on the tape. A pair of spools 18 and 19 is used to store the tape. For the indicated direction of travel of the tape, spool 18 functions as the supply spool, and spool 19 functions as the takeup spool. A clutch 110 controls whether spool 18 or spool 19 functions as the takeup spool. A belt 111 transfers power from a hub 112 to clutch 110. When the tape cartridge is loaded into a disc drive, hub 112 is connected to the shaft of the disc drive motor so that the power to feed the tape is provided by the disc drive motor.
Because disc drive motors typically have only a relatively low amount of power, it is important the the disc drive compatible tape cartridge have only a minimal amount of inherent friction. As a result of the reduced friction, when the tape cartridge is removed from the disc drive, the tape can unwind from the spools during handling and accumulate spirally or randomly in the spool area. In addition, when the disc drive motor is stopped, the inertia of the tape and the spools will tend to make the tape unwind from the spools.
The tape that has wound off of the spools can become folded and creased on the spool, thereby damaging the tape and possibly jamming the cartridge. Also, when there is slack in the tape when the disc drive motor is powered on, the disc drive motor will initially be loaded only with the inertia of the tape that is being moved by the disc drive. At the point at which all of the slack has been removed, the power is suddenly applied to rotation of the supply spool, thereby producing shock loading of the tape that can damage the tape, the cartridge, and/or the disc drive. In one version of disc drive compatible tape cartridge, a brake is included in the disc drive to stop rotation of the spools when the tape cartridge is removed from the disc drive. In this embodiment, an arm is rotated against the side of a spool when the tape cartridge is removed from a disc drive. However, this embodiment does not prevent unwanted unwinding of the tape while the cartridge is still in the disc drive and does not slow down rotation of the spools when power to feed the tape is terminated.